An experimental study and a regression analysis were carried out to find out the growing patterns of Egeria densa at three different NH4+-N concentrations as low (2 mgL-1), medium (4 mgL-1), and high (6 mgL-1). DO concentration during respiration and photosynthesis was monitored in daily basis while plant morphological characteristics were examined with harvesting at six-day interval. There was no any significant difference in morphological characteristics indicated at low and medium NH4+-N concentrations (p>0.05). On contrary, the total plant length at high NH4+-N concentration has deviated significantly (p<0.01) from other two concentrations after 15 days since commencement of the experiment. Averaged relative growth rates (RGRs) were recorded as 0.05, 0.04 and -0.01 mgday-1 in terms of dry weight production for low, medium and high NH4+-N concentrations, respectively. The results of the non-linear regression analysis explained the effect of low and medium concentrations over high concentration of NH4+-N, while the medium concentration provided the best correlation coefficient (r2 = 0.901) for the modeled equation. These results can be used in optimizing the effects of E.densa at tertiary wastewater treatment.
Temporal changes in the mutagenicity of roof runoff water from an inclined tiled roof were investigated during two rain events (Surveys 0007 and 0011). Mutagenicity was evaluated by the pre-incubation method using Salmonella typhimurium strains TA98 and TA100 with and without S9mix. The following conclusions were obtained: (1) The first flush phenomena on mutagenicity were observed in Survey 0011, but not observed in Survey 0007, as well as PAHs. (2) Although the relationship between mutagenicity and PAH concentration was unclear under some conditions of the Ames test, mutagenicity and PAH concentration showed a similar trend in most cases. (3) This suggested that one of the main causes of mutagenicity of roof runoff water was a combined effect of many PAHs and their derivatives. (4) The soluble samples showed mutagenicity without S9mix. This could be due to nitrated PAHs.
Eucalyptus biomass char was produced by a fluidized bed reactor. The influence of pyrolysis temperature and heating rate on char yield was investigated. The pyrolysis temperature ranged between 673K-1673K. When rapid pyrolysis, char yield was almost constant at about 15%, between 773K-1173K, while was decreased to several % with increased temperature. When slow pyrolysis (10 K/min), char yield was almost kept at 22-17% between 1173K-1673K. Fixed carbon and ash yields in fast pyrolysis char were investigated by NC coder. Fixed carbon yield based on the dry biomass was monotonously decreased and ash yield gave the maximum in the vicinity of 1073K. SEM picture was also given to elucidate the effect on its structure of pyrolysis temperature and heating rate.
A lot of trees or shrubs has been planted in the oil fields of the central part of the Taklimakan Desert since 2003 accompanied with petrol exploitation. A meteorological observatory was set up in one of the oil fields before the plantation. The data from the station and 5 other surrounding meteorological observatories in the desert were analyzed to clarify the greening amenity in the central part of the big desert. It is clear that the atmospheric environmental condition is becoming better as the wind speed and air temperature are decreasing and humidity is increasing. However, increase in winter air temperature was not appeared as other oases around the desert. Reductions in wind speed due to tree planting have strengthened the local cooling system and enhanced temperature inversion in the small basins between compound/complex linear dunes in the central part of the desert.
Tetraethoxysilane (TEES) is produced as a major by-product from the disproportionation of triethoxysilane (TRES) during the non-halogen process to produce monosilane SiH4 for polycrystalline silicon manufacturing. In this study, the hydrolysis of TEES was carried out to produce silica fines in the gaseous phase as an effective use of the TEES by-product. We expected to attain higher conversion under lower temperature than in the case of tetramethoxysilane TEMS. One-hundred percent conversion was obtained under 923 K and above, and such temperature is relatively low compared to the 100% conversion temperature of TEMS, which was more than 1123 K.
Long-term changes in the precipitation data at Sturt Meadows were analyzed by the Mann-Kendall statistics and the Lepage test. Yearly and spring precipitation increased significantly from 1910 to 2008, and the significance levels were p < 0.10 and 0.01, respectively. The data of daily precipitation were classified into two groups (class 1-4 and 5) separated by the distribution of the data, and class 1-4 precipitation increased significantly. There were 4 significant-climatic jumps (1925-27, 1963, 1979-1982 and 1993) by results of the Lepage test. The averages of yearly precipitation during whole years and the latest period are 215.0 and 280.9 mm/year, respectively. The averages of monthly precipitation in February, October and November during the latest period (1993-2008) is higher than those in the previous periods. That in February during the latest period was especially heavy, when the mean precipitation in February was six times higher than that in the previous period. This change was attributed to the increase in the frequency of storm events in February during the latest period. Monthly precipitation exceeding 100 mm/month in February was recorded three times (1995, 2001 and 2006), and this occurred only 2 times in previous periods (1925 and 1975).